The long-term goal of this research project is to further study and analyze the cellular, morphological and biochemical events which occur during the transdifferentiation of pigmented iris epithelial cells (IECs) and neural retina pigmented epithelial cells (RPE) from the eye of the adult newt Notophthalmus viridescens into lens fibers and neural retina during lens and neural retina regeneration. We will place emphasis in the analysis of the dedifferentiation and redifferentiation phases of these two regenerative processes. Experiments will be conducted both in vivo and in vitro. This project has the following specific objectives: (1) to measure at different time intervals during the transdifferentiation process the intracellular levels of cAMP on dorsal irises and IECs under cultured conditions. (2) To measure protein kinase C activity at different time intervals during lens and neural retina regeneration in vivo. (3) To study the role of cytoskeletal components of IECs and RPE cells undergoing dedifferentiation under cultured conditions and treated with adenosine, cAMP and related compounds. This will be monitored with antibodies against different cytoskeletal proteins and immunofluorescence techniques. (4) To study alterations in membrane sugars of IECs and RPE cells during lens and neural retina regeneration. This will be done using a battery of lectins and immunofluorescence techniques. (5) To study the effects of extracellular matrix (ECM) components during the transdifferentiation of IECs and RPE cells into lens fibers in vitro. Cell-type conversion of the cells into lens fibers will be monitored using antibodies against lens specific proteins. Transdifferentiation of RPE cells into neural retina both in vivo and in vitro will be studied using monoclonal antibodies for the identification, particularly of photoreceptors and amacrine cells. (6) To study the effects of growths factors during the transformation of IECs and RPE cells under cultured conditions using the same approach as in objective 5. (7) To provide students with the opportunity to get involved in the main scientific activity that is research. In this project further efforts will be made to obtain basic information on the control mechanisms of dedifferentiation in both systems. It is expected to apply the ideas obtained in this research project to the dedifferentiative process which do occur during carcinogenesis. This research project will continue to provide the students with the opportunity to learn different techniques and to get involved in the main scientific activity that is research and to motivate them to pursue careers in different areas related to biomedical research.